1. Field of the Invention
This invention relates to an injection molding machine, particularly to an injection molding machine for processing synthetic materials, comprising a machine base, a movable mold carrier and a stationary mold carrier fixedly connected with the machine base and with a supporting element that supports a closing mechanism provided for moving the movable mold carrier. The supporting element is linked flexibly with the stationary mold carrier by at least one force transmitting element adapted to take up forces occuring when the mold is in a closed position. Furthermore, the injection molding machine comprises a motion path along which the movable mold carrier is displaceable.
2. Description of the Prior Art
An injection molding machine of this kind is, for example, known from German Utility Model 92 12 480. In this injection molding machine a supporting element and a mold carrying plate are jointedly and tiltably connected with a machine base of cast iron, which deviates the closing pressure occuring during the closing process and the lifting force occuring between the supporting element and a mold clamping plate during injection. In order to avoid evasive movements of the mold plates, known as "cherry-stone effect" and to obtain parallelism of the mold, guiding devices are provided for the movable mold carrier, to guide it parallely to the other mold part, especially in case of eccentric loads, for example, by off-center mold cavities. The principle followed is to form the machine base so rigidly that it is only minimally deformed under the occuring forces and additionally, to keep away the remaining deformations from the mold by the jointed bearing of the mold carrying plate and the supporting element. However, the manufacture of the cast iron machine base, due to its size, causes difficulties, namely concerning blowhole formation. Since the stationary mold carrying plate is jointedly coupled at the machine base, a nozzle cannot be reproduceably adjusted to zero point, due to the occuring forces during the closing process.
German Published Patent Application 42 30 348 discloses a machine, in which a supporting element and a mold carrying plate are jointedly connected with a machine base of cast iron, which deviates the forces occuring during the closing and the injection process. The movable mold carrier and a supporting element are jointedly connected by a toggle mechanism, at which a driving device is freely suspended at link points of toggle levers, whereby evasive movements of the movable mold carrier are avoided. In this arrangement the machine base is formed according to German Utility Model 92 12 480.
A further injection molding machine of this kind is known from European Post-Published Patent Application 554 068. In this machine a clamping means is provided, that is deformable without essentially deviating stresses originated by the moving- and injecting forces into the machine base. The clamping means, together with the other parts of the mold closing unit, constitute a closed strength framing and can be optimally adjusted to the respective operating conditions. The deformations have little influence on the position of the fixed clamping plate. Peripheral units screwed at the machine base, such as handling- and withdrawal devices, are not influenced by the deformations, so that an exact triggering of the deposit points is reproduceably possible. The horizontal zero point of the nozzle remains at zero, even under maximum locking pressure, since the zero point of the nozzle is fixed by the rigid connection between the unremovable clamping plate and the machine base. The principle followed is to deviate the deformations by a clamping element, which has no influence on further machine parts, whilst the closing forces are unhinderedly summoned up in the closing direction. Due to the decoupled deformations, a safe closing of the injection tools during the whole injection process is guaranteed. The application of guiding rods can be almost completely omitted, whereby it is made possible to realize a better access to the injection tools as well as to achieve shorter retrofit-times. Indeed, the bearing points for the clamping element in this arrangement are arranged directly at the stationary mold carrier and at one supporting element. They slide in eyes of the clamping means. As a result, there are, on the one hand, difficulties with regard to the mold parallelism, and on the other hand, the joints are worn so much in the course of the machine life, that a complete exchange of the mold carrier and the clamping element is inevitable.
From Austrian Patent 372 333, there is furthermore known a machine for processing synthetic materials in that both mold carriers are movably arranged at a C-shaped clamping element. Due to the arrangement of the mold carriers, the deformation forces, occuring when locking the mold, can in fact be deviated by the clamping means, however, it is not possible to reproduceably produce an exact nozzle contact point, since both mold carriers are movably supported, so that this device does not satisfy the requirements made to an injection molding machine for processing synthetic materials.